HYDRAULIC CONDUCTIVITY OF HOMOGENIZED TAILINGS FROM HARD-ROCK MINES

Tailings produced by milling for ore extraction from hard rock mines, which range in size from clay to fine sand, have relatively low hydrau lic conductivity, k. The value of Ic must be known with a certain degr ee of certainty to analyze consolidation and seepage conditions in and around railings ponds. In this paper, the authors present the results of a laboratory investigation on hydraulic conductivity of homogenize d tailings from hard rock mines. After describing some of the basic pr operties of four different materials, including mineralogy, grain size , Atterberg limits, compaction characteristics, and consolidation curv es, permeability test results are given, The hydraulic conductivity va lue usually varies between 10(-4) and 10(-5) cm/s. The effect of vario us factors on this value, including void ratio and grain size, is then discussed in relation to predictive models. It is shown that a modifi ed version of the Kozeny-Carman equation, in which a tortuosity factor and a grain-size distribution function ale included explicitly, can r epresent the data very well. The equation is also checked against resu lts taken from the literature on similar types of materials.